This invention relates to a method of and an apparatus for converting a first series of pulses into a second series of pulses having a frequency proportional to the first series and, more particularly, to an instrument for measuring the velocity of a rotating element and converting the series of pulses representative of the rotational velocity into a form which can be easily displayed by an RPM meter.
Accurate measurement of the velocity of a rotating gear is desirable. When convenient, a sixty-tooth gear is included in or connected to the rotating system. A proximity detector sensing the teeth of the sixty-tooth gear is coupled to an electronic counter having a one-second time base. This provides a direct reading of RPM. However, if a sixty-tooth gear (or multiple thereof) is not available, a variable time base counter must be used to convert the number of pulses received from the gear into a form readable by the electronic counter having the one-second time base. Adjustment of the time base is required and the accuracy of the system depends upon the adjustment of the time base. Adjustable time base counters are expensive and are often not readily available.
I have developed a method and apparatus for converting the pulses from a gear to the number of pulses which would be generated by a gear having sixty teeth and rotating at the same velocity as the gear being measured.